The present invention relates to an expanded composite structure and a process for making an expanded composite structure.
The manufacture of open-celled, lightweight plastic parts has been heretofore accomplished by one of two approaches. A first known approach involves forming the matrix of the structure by physical gas injection or the evolution of gas byproducts during a chemical reaction. A second known approach involves using a fiber mat having a desired degree of openness and dip-coating or spraying the fibers with an adhesive material, and then allowing the coating to set, giving the mat a monolithic structure.
Both of these approaches suffer from drawbacks or disadvantages in their use. The first approach requires either a physical mechanism for blowing gas into the polymer, or special use of chemicals which will evolve gas to produce the expansion. The second approach is useful essentially only for low fiber loadings in the fiber mat as the mat is coated and set in an uncompressed state.
It is an important object of the present invention to provide fiber-reinforced structures wherein the fibers are coated with a plastic material and wherein the fiber density is considerably higher than in the original fiber mat while maintaining at least a partially open-celled structure.
It is an additional object of the present invention to provide a process for manufacturing fiber-reinforced structures having interstitial voids produced by expanding a compressed, substantially void-free fiber mat under controlled conditions.
It is a further object of the present invention to provide a process for manufacturing an expanded fiber composite structure wherein a plastic impregnated mat having interstitial voids also has an additional polymeric component introduced to fill the voids.
It is a further object of the present invention to provide a product made by any of the above-identified processes comprising a reinforced composite fiber mat having a wide variety of potential commercial applications including use as thermal insulation, structural members, and filtration devices.